Screw clamp



K. KISSENDORFER SCREW CLAMP Filed May 8, 1922 .Zin ven fd?? Patented pr. l?, i923,

KARL KISSENDORFER, Oli' OBERNDORF-ONTHENECKR, GERMANY, ASSGNCB 'ITO WAFFENFABRIK IVIUSER, A. G., OF @BERNDORF-ON-TI-IlENECKAR, GERMANY.

SCREW Application filed May 8,

To all wlw/m, t may conce/m:

.Be it known that l, KARL Krssnnnonrnn, a citizen of the German Republic, residing at No. 22 Rottweilerstrasse, in the city of Oberndorf-on-the-Neckar, Germany, have invented certain new and useful Improvements in Screw Clamps (for which l have filed the following applications: in Germany, February 11, 1922; Austria, March 10, 1922; Czechoslovakia, March 10, 1922; Yugoslavia, March 4, 1922), of which the following is a specification.

This invention relates to a screw-clamp or cramp of the kind comprising a rigid bow or U-shaped body the one shank of which affords the stationary jaw for the work to be clamped, while the other shank has its end formed into a threaded opening or eye for the reception of a manually operable threaded spindle, the inner end of which affords the other jaw of the holdfast or cramp.

Adjustable tools of the described type also comprise a releasing means for disengaging the Ithreaded spindlefrom the female thread of its guiding shank in order to allow an initial or preliminary rough adjustment of the jaw in accordance with the size of the work to be clamped, and to then engage the female thread with the spindle for the subsequent manual operation of clamping the work fast between the jaws with the aid of the spindle asis usually done in ordinary holdfasts.

Said releasing means preferably consists of a segmental portion of the eye pivotally connected to the latter and having 4on its. semicylindrical innerface a female thread conforming to the spindle thread, while all the other portions of the said eye are not threaded, so that when the aforesaid segmental portion is turned out about its pivot the spindle will be free to axially move inv the eye, and when said portion is turned in or closed, the spindle will be gripped by the female thread thereof and cannot move eX,- cept on the path or track of the thread.

Now, it `has beenfound,that, when the thread of a screw-clamp of the adjustable type, as above described, has worn out by frequent use, the axial pressure of the spindle vwill be diverted laterally, acting to disengage the pivotal threaded portion of the eye, so that, ifthis occurs, the spindle will be free to move in the Unthreaded portion CLAVIP.

1922. Serial No. 559,394.

pf the eye and there will be no clamping ef Zect.

The object of this invention is to remedy this defect by providing a means for locking t-he pivotal threaded portion of the eye, when closed, with the aid of the pressure force, so that whenl the spindle is under clamping strain there will be no liability for the threaded eye portion to disengage from the spindle.

The specific .construction of the tool is fullyillustrated in the drawings, in which- Figure 1 is a side elevation of the screwclamp with the improved 'thread guiding and locking arrangement in closed position and with the work clamped tight between the two aws Of the tool,

Figure 2 is a similar view with the work loose in the gap between the jaws,

Y Figure 3 is a section on the line lli-B of vFignre 1, n

. Figure 4 is a section on the line of A-B ofFigure 2,

Figure 5 is a section onthe line C-D of Figure 1 and Figure 6 is a section on theline of C-D of Figure 2.

Likeletters designate corresponding parts in all of the figures of the drawing.

Referring to the drawing the letter a designates the segmental portion or member of the eye having the female thread and pivotally connected with or hinged to the upper shank of the bow c by means of a bolt it the innerend oi' the segmental portion or member@ a lug d is provided, said lug having a curved or sloping face or incline at its outer end to conform to the correspondingly shaped recess 7"' in the contacting face or end of the unthreaded major portion z' of the eye. The member a commonly assumes a position with relation to the eye portion t' as shown in Figures 1 and 5;

The pivot or bolt consists in the shown embodiment of the invention of an ordinary screw-bolt with its shank firmly screwed into the ear 7c of the member a. and with its head loosely fitting in a bore Z of the upper shank ofv the bow c. A coiled spring g is provided on the bolt in the bore Z so as to abut with its ends against the head of the bolt and the bottom face of the bore respectively and thus keep the member a constantly in Contact with the unthreaded portion i of the eye, as shown in Figure 1, as long as the member a retains its closed position.

lit", however, the spindle e, instead of being under strain, as in Figure l, is loose, as in Figure 2, and consequently also t-he threaded member a is not under strain, the latter can be turned out or opened by means of the tail or handle 7L, whereby its female thread is disengaged from the thread of the spindle e and the parts are caused to assume the position shown in Figure 2.

ln consequence of the oscillation ot the member a about its pivot Z) the lug d slides outwards over the inclined `tace ot the recess troni the position illustrated in Figure 3 to that shown in Figure (i, and at the same time the contacting' faces of the Unthreaded portion if of the eye and of the member a separate against the action of the spring g, 'from the position shown in Figure l to that illustrated in Figure 2. The spindle c then is thoroughly Jrree within the eye, as shown in Figures 4f and (3, and can bespeedily adjusted to the size oiz the work a, as shown in Figure 2. This done the handle 7i is released so that by the action oi the spring g, the member t is drawn inwards and upwards with the lng (l sliding` back into the recess until the female thread of the member a again is in engagement with the thread of the spindle c. ln turning the latter down by means of its handle m to engage with. the work n and by forcing the jaw into firm contact with the work n as illustrated in Figure l, the pressure ot the thread of the spindle on the thread of the member a en sures a firm locking engagement of the lug rZ in the recess j", as shown in Figure 5, so that the member a cannot disengage from the spindle thread, even in case the threads are considerably worn.

F rom the foregoing description, it will be seen that simple and eiiicient means are herein provided for accomplishing the objects of the invention, but while the elements shown and described are well adapted te serve the purposes for which they are intended., it is to be understood, that the invention is not limited to the precise construction set forth, but includes within its purview such changes which may be made within the scope oi the appended claims.

Having' now particularly described and disclosed the nature of the invention and in what manner the same is to be performed, what is claimed is:-

l. An adjustable screw-clamp, comprising :s assessealso a recess; a spindle associated with the opening of said shank; a tl read member havini; a bolt for pivotally securing the member 'to the last-named shank, and provided with screw threads adapted to coact with said spindle; a lug on said member adapted to coact with said recess; and a spring on said bolt for forcingr said member against said spindle.

2. An adjustable screw-clamp, comprising a bow haring;` a shank at each end, one Oi said shanks beine' provided with an opening` and also a recess haringan inclined surface; a spindle associated with the opening,r oi said shank; a thread member having a bolt ioi' pivotally securing the member to the last-named shank, and provided with screwthreads adapted to coact with said spindle; a lug on said member adapted to coact with the inclined surface ot said recess; and a spring1 on said bolt for forcing` said member against said spindle.

jin adjustable screrclainp, comprising a bow having' a shank at each end, one of said shanks having' an opening` therein, and also a reccssha.y an inclined edge; aspiridle associated with the opening of said shank; a thread member having a 'bolt itor piyotally securino the member to the lastnamed shank, a provided with screw hieads adapted to coact with said spindle; a lug on said member adapted to coact with said recess; and a spring lon said bolt for forcing said member against said spindle, said thread member being adapted to move parallel with said spindleby means of said bolt when the spindle is rotated.

s. An adjustable screw-clamp, comprising a bow having a shank at each end, one of said shanks having an openini therein, and also'a recess haa/inn` an inclined edge; a spindle associated with the openingi of said sha-nk; a thread member haring;` a.. bolt tor pivot-ally securing the member to the last-nained shank, and provided with screw threads adapted to coact with said spindle; a lug on said member adapted to coact with said recess; and a spring,1 on said bolt for forcing said member against said spindle, said thread member being! adapted to more parallel with said spindle by means of said bolt sliding in its socket in said shank and to rotate against the action of said spring:r when said lun" is out of engagement with said recess.

ln testimony whereof l aiixed my signature.

KARL irissnnnoarnn. [Le] 

